Aged 45, I have performed this test and can hear up to only 15KHz.Does it make any sense building my digital library over 320Kbps mp3s? Useless using FLAC or any lossless format if cannot hear anything above 15Khz, unless high bitrates will improve lower frequencies too....

I guess the best way to find an answer would be encode a lossless file with both 320 kbps and some lower bitrate. Then do an abx test and if you can tell them apart increase the lower bitrate. If you cannot tell them apart anymore increase the bitrate a bit just to be on the safe side.

There are other reasons besides low-pass filtering to choose lossless, or a particular bitrate lossy.

Besides, most lossy encoders allow you to change the low-pass frequency indepently, so you could choose a high quality encode with a low-pass taylored to your own hearing.

Also, just because you can hear a 15 kHz tone doesn't mean that you need to encode up to 15 kHz. You should try a listening test in which you take some music with lots of high frequency content, then vary the low-pass filtering until you find the frequency above which you can't hear a difference.

Or, you could simply say the hell with it and encode with the default low-pass.

I don't believe in using low pass filters because I want my dog to get the full enjoyment of all of those really high frequencies.

Actually, I've stopped trying to screw around with any of the settings on any of the codecs I use. Since storage is cheap, I just crank Lame up to -V0 and just let Lame do its thing.

This thread did make me wonder something: Have modern codecs really improved in the years since I started listening to MP3's, or has my hearing just deteriorated to the point that things that used to bother me are now inaudible? After all, I first started experimenting with MP3's when I was in my late twenties and now I'm 45. To test this, I encoded a song at 128 kbps CBR with the oldest encoder I could find: Blade Encoder (circa 2001). It sounds really awful! It's good to know that my hearing isn't totally shot.

In principle, it is not a good idea to perform just one listening test and then adjust all your files to what you can't hear on that particular sample ...

As far as encoders go: Yes, they have improved. The listening tests posted regularly in this forum, have often chosen an old encoder as the low anchor, and it often verifies (with the appropriate statistical significance) as inferior.

Oh well, I will just FLAC everything for archiving and then encode to MP3/AAC for portability!

I'm trying to keep things simple, so I store everything in FLAC and, when moving stuff to my portable (Sansa Clip+Koss Porta-pro), convert everything to 190 vbr. At a home-machine disc-space is so cheap and FLAC:s compression efficient enough, that going for anything more seems to be wasteful.

I can just barely hear a slight difference between 190 and 160 mp3s on good headphones, but the difference is negligible (I have no experience whatsoever listening to compressed files on a good quality home system with speakers and the acoustics of the room etc. etc. So I might be talking complete bollocks here). Storage space is far more in demand on a portable device, so while a rockboxed Sansa Clip can play FLAC, I haven't found it useful. Converting itself takes about a minute (Foobar+LAME) so it's not a problem. The difference in filesize between 190 and 160 is not large enough for me to go lower.

There is still one good reason for buying CDs or lossless encoded files. If at any time you need to encode to lossy, and you need it in a different codec or at a different bitrate, then encoding from lossless will give you the best possible quality. When you transcode from lossy to lossy the quality may be just fine, but there is no way to be certain. Sometimes lossy transcoding doesn't work out that well.

I'd be careful deciding upon the exact lowpass according to just this listening experiment though I do think using a lowpass does make sense. I'd just go a bit higher than just 15 kHz.

This means that in my case there's no sense in buying a CD or anything encoded over 192kbps

There's more than frequency response especially when it's up to lossy encoding.I also buy CDs when there are at least a few songs on an album I really like (otherwise I buy 320 kbps mp3s) because I want to have a lossless source though I only listen to mp3s.

Aged 45, I have performed this test and can hear up to only 15KHz.Does it make any sense building my digital library over 320Kbps mp3s? Useless using FLAC or any lossless format if cannot hear anything above 15Khz, unless high bitrates will improve lower frequencies too....

Higher bitrates improve everything (measurably - what you hear depends on you + the codec). Lossless means not having to worry, and being able to transcode to mp3 (or anything else) without worrying about the quality of the source.

For portable use, I'm quite happy with a 16kHz low pass. mp3 is less efficient above 16kHz. I can just hear the 18kHz tone if I crank the volume up. At a normal listening level, I can just hear the 15kHz tone.

I could hear 14 kHz at a reduced volume but still pretty loud, but I couldn't really hear much if anything at all at 15 kHz. It's a bit hard to know if I can hear 15 kHz at all because there are loud clicks at the start and stop of playback that mask the tone going from off to on. But even if it was there it's at least 99% attenuated anyway so that's a bit of a moot point.

I also worried a bit about the playback path from web browser to speakers, but I'll assume if I can't hear a tone, it isn't there, it would be the opposite case I would worry about.

Anyway it was interesting to find out where my hearing is at, thanks for passing this along. I'm 41 BTW.

At least now I can downsample all my FLACs to 32 kHz and put off buying a new hard drive for a while

Is there any benefit at higher bitrates on low frequencies (bass)? Seems not

I'm not sure that many people know or ever care about the effects of low bitrates on just bass.

The deleterious effects of low bitrates is not restricted to certain frequency ranges. Low bitrates cause musical tones to be less pure. The lack of purity is not necessarily the addition of tones that were not there, although that can happen. The lack of purity can have the opposite effect which is to remove or mask tones that were there. In addition not just tones are affected but also the shaping of bursts of tones can be effected.

Low bitrates can cause something like false echoes to be added, for the richness of musical sounds to be reduced, and for impulsive sounds to be stretched out or even lost.